Covanta Sustainability Report: GHG Emisions Drop 33%

Energy-from-waste firm Covanta Energy’s total greenhouse gas emissions fell around 33 percent from 2010 to 2011, according to the company’s latest sustainability report.

Year-on-year the company reduced its absolute greenhouse gas emissions from 11.8 million to 7.9 million tons of CO2 equivalent. All but 51,000 tons of those emissions were direct emissions from Covanta’s facilities.

The company has a broad goal of reducing overall emissions associated with its facilities, specifically with regard to dioxin and mercury. Covanta’s trends for both mercury and dioxin demonstrate a year-on-year improvement, where the majority of results “are in the low end of the range,” the report says. By 2011, more than 94 percent of Covanta’s monitoring results showed dioxin emissions of less than a third of the EPA’s regulatory limit. Also by 2011, more than 95 percent of Covanta’s monitoring results showed mercury emissions of less than a fifth of the EPA’s regulatory limit.

As a provider of energy-from-waste, Covanta’s basic operations are carbon negative, the company says. The decrease in absolute emissions was accompanied by a 29 percent increase in the emissions the company is responsible for removing from the atmosphere.

In 2010, Covanta’s net greenhouse gas footprint from operations was -13.4 million tons of CO2 equivalent. This metric improved to -17.3 million tons of CO2 equivalent in 2011.

The company’s operations in 2011 avoided 18.1 million metric tons of CO2e from being emitted, by diverting waste from landfill. This was up from 17.9 million metric tons in 2010 and 16.8 million metric tons in 2009.

Based on estimates using the EPA’s Decision Support Tool, Covanta says about one ton of CO2-equivalent is reduced relative to landfilling for every ton of waste processed at an energy-from-waste facility. In addition, each ton of waste processed for energy eliminates the need to consume about one barrel of oil or one-quarter ton of coal at a fossil fuel-fired facility, the report says.

Water is essential for Covanta’s waste-to-energy processes. At Covanta plants, water passes around the energy-from-waste heat exchange equipment and turns to steam, which, in turn, drives a turbine to generate electricity.

Covanta has a broad and ongoing goal of introducing initiatives that reduce overall water use at its plants and allow the use of lower-quality water. The report does not include specific figures for overall water use but it does include a case study from one plant.